Cell-free DNA in Liquid Biopsy as a new biomarker in curative surgically treated oropharyngeal carcinoma

Introduction:

Head and neck tumors are already well advanced at first diagnosis. Despite the implementation of an aggressive and multimodal therapy, the prognosis of patients with advanced head and neck cancer remains dismal. Currently, biomarkers are missing to measure disease burden and/or response to therapy. The analysis of circulating tumor derivatives representing a patient's tumor signature were found as a result of increased cellular turnover in the blood and has already been studied in other cancers. Thus, liquid biopsy poses a new challenge in non-invasive head and neck diagnostics.

Methods:

A prospective pilot study at Heidelberg University Hospital was performed on HPV-positive and HPV-negative oropharyngeal carcinoma patients (control), who were primarily surgically treated with or without adjuvant radio(chemo)therapy. Pre- and postoperative follow-up blood samples were carried out. Tumor tissue samples were tested on p16 using immunohistochemistry, and the cell-free DNA (cfDNA) from the patient's blood was analyzed by PCR.

Results:

Initial study results confirmed that in the preoperative blood sample prior to initiating therapy, high viral DNA detection was found in HPV-positive oropharyngeal carcinoma patients, whereas no viral DNA was detected in the blood after tumor extirpation. Our theory is that if the viral DNA decreases in the postoperative blood sample and rises again in the follow-up blood, tumor recurrence is assumed.

Conclusions:

Liquid Biopsy has the potential to detect tumor relapse at an earlier stage in p16-positive oropharyngeal carcinoma and to elucidate the enormous heterogeneity of the head and neck tumor by serial blood collections, which is the prerequisite for personalized treatment.

Publication History

Publication Date:
23 April 2019 (online)